Slow In Slow Out

The principle of Slow In Slow Out means slowing down the speed of animated frames when reaching a main pose while also accelerating again when leaving a main pose. With doing with the animators creates a more realistic and fluent form of animation.

Example:


Animator: Soluni Lodunis
Animation Type: Hand Drawn
Link: http://www.youtube.com/watch?v=vsMY_7ssssU
This piece shows this principle quite well for that you can clearly see the more frames during the return to the main frame compared to the less amount frames found in the leaving action of the runner.